pieper



March 6, 1928.

H. PIEPER SERVO BRAKE Filed April 15. 1926 s sheets-sheet 2 EGE.

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,n 1;@ venan 1706,12' .ge/16er' @www March 6, 192sm ril 15 1926 H. PIEPER v sERvo BRAKE Filed A@ 3--4115-"0 Patented Mar. 6, 1928,

UNITED STATES narrar omer.

HENRI PIEPER, 0F BRUSSELS, BELGIUM, ASSIGNOR 1'0 COMPAGNIE Ylill'TER].\`1'A'I['l'.O1\l'.AIll| DES FREINS AUTOMATIQUES, ECIETE NNYME, 0F LIEGE, BELGIUM.

SERV() -B BAKE.

Application led- April 15, 1926, vSerial No.

. The servo brake system described in the application No. 757,747 isadapted ior use on vehicles provided with an internal conibustion engine. The suction oi this engine is employed in order to release the brakes Which are applied by mechanical, hydraulic or pneumatic means. y

In vehicles of this description it frequently occurs that immediately after the `pedal which controls the application oi' the brakes has been released, the accelerator establishing the admission yot the explosive Amixture to the engine is actuated with a view to accelerate the speed ot the vehicle. lt may happen therefore that in certain cases this admission Which produces a decrease in the partial vacuum existing in the suction duct of thejengine tales place betere the partial vacuum which previously7 existed in the duct has hadv time to eect the complete release ot the brakes.

The present invention has for its object to obviate this disadvantage.` lith this end in vievv the invention involves the use oi a vessel in which the suction of the engine produces a partial vacuum during the periods 1 when the partial vacuum which exists in the suction duct is fairly high.

An automatic valve is interposed betvveen the said vessel and the suction duct in such a Way that it becomes pressed upon its seating as soon as the partial vacuum existing in the suction duct falls. The duct transmittingthe partial vacuum to the brake releasing cylinder communicates Withthis vessel in such a way that `release may be obtained Whatever be the partial vacuum produced at the moment under consideration by the engine.

The invention further relates to a particular advantageous construction of the Adist-ributor controlling the entry into action of the bralre applying and releasing devices.

This distributor, which comprises a sliding member, actuates in one direction the4 closing member controlling communication with the atmosphere and in the other that controlling communication with the partial vacuum. This sliding member is attached to a diaphragm subjected upon one of its surfaces to the action of atmosphere pressure and upon the other to the action of the partial. vacuum existing in the releasing cylindein 'The said member may further be sabicaisa, and in. Belgium necember 24, 1925.

jected to the pressure of a spring opposing the action ot the atmospheric pressure and may be connected to the brake controlling pedal or lever through the intermediary ot' another spring.

The above said patent application describes a servo` bralre in which the braking force is produced by employino, lfor the ap.- plication of the` brakes, a reserve ot energy placed upon `each vehicle, release being obtained by causing a partial vacuum produced upon one ot them to act upon pistons connected to the brake mechanism of each vehicle, which partial vacuum is produced in one of the latter' and transmitted through# out the Whole length of the train.

The present improvement involves an arrangement according to which the entry into action of a brake applying and releasing means disposed upon each vehicle is controlled upon each one of the latter by a ydistributor itself controlled by the pressure of a fluid contained in a second duct extending throughout the Whole length of the train. y

The said distributor Will be maintained in the position corresponding to release when a partial vacuum exists in the said controlling duct. The latter may be put into communication With a vessel in Which exists a partial vacuum produced by the device which produces the partial vacuum necessary for the release o't the brakes.

With a view to speeding up the application of the brakes throughout the Whole length of the train the above mentioned distributor may causethesaid controlling duct to be put into communication with the atmosphere upon the vehicle Where the said distributor-is located and this will be effected when one of the members of the distributor has completed a stroke in the direction for the application of the brakes exceeding a certain length.

The invention also provides for the use ot additional vessel in which a partial vacuum exists, such vessel to be disposed upon certain vehicles With a view to allowthe brakes to be released Without the i tance of the vehicle provided with the device producing the partial vacuum which transmitted throughout the Whole length of the train..

The additionalk vessel also be til) mounted upon an additional duct extending over the whole length ol the train, the tapping being made trom the vehicle producing the partial vacuum.

The accempanyijngdrawing illustrates by Wajvr ot example some forms ot the invention.

In this drawing:

Figure l shows diagrammatically one form ot' the invention in the case ot a vchicle provided with an internal combustion engine,

Figure Q illustrates diagrammati'cally the members carried bv the vehicle provided With the device producing the partial vacuum as well as the member carried by one ot the other vehicles.

Figures ffl and 4- show inodiiied forms ot one oi these n'ieinbers.

Figure 5 a view similar to Fig. 2 in the case ot the employment oil a releasing vessel disposed upon certain vehicles.

In the case shown in Figure l. the brake mechanism t not shown) will be connected to diilerential pistons Ll, 5 i'or example through the medium ot the cross member 76. The piston' is moved towards the position for application o t the brulies b v the action ot a fluid under pressure ycontained in the vessel 6. Release is produced by communicating a partial vacuum through the duct 2 into the releasing cylinder 3 in which moves the piston l. The duct 2 is connected through the interposition of a distributor, which is more particularlj)V7 described hereinafter7 to the suction duct l ot the engine.

VThis connection is ell'ected thiough the mediumv otI a duct l openingl into a vessel 71 and a second duct l2 leading from said vessel. to the suction duct l; such connection being controlled by means of an' automatic valve `72 which located in the duct 2 and which opens in an upward direction, returningl upon its seat as soon as the partial vacuum in duct l becomes less than that which exists in the said vessel 7l.

It will be apparent that this vessel may be omitted, on condition that a duct is provided which connects the automatic valve 72 and a valve 7 associated. with the previously-mentioned distributor; the capacity' ot such duct being` equal to that oit the vessel.

A characteristic feature ot the invention consists in the use ot' an automatic valve such as 72 interposed between the suction duct l and the vessel or reservoir 71; such valve opening only7 when the suction :in said ductl is greater than that in said vessel, and thereby permitting' suilicient suction for the operation of the brakes to be maintained While the en ejine is running.

The distributor comprises a sliding member 73 which, when it is moved upwards as shown in `Figure l, opens the valve 7 controlling communication with the partial vacuum in vessel 7l. This valve 7 is con- ,municati on stantly pressed towards its seating by a s ing` 28, lllhen the member 73 is moved downward7 it permits the valve 7 to close and opens the valve 8 that Controls comwith `he atmosphere, which valve 8 is 'constantly7 pressed towards its seating` by a springl 33.

These opening,Y movements are produced through the medium oit a rocking' lever 7st adapted to bear Vupon the spindles of the valves and to operate throughv the said sliding` member' 73. n y i The latter is secured to a diaphragm 33, one ot the surfaces ot which is subjected to atmospheric pressure while the other surtace is acted upon by the pressure existing in the releasing cylinder 3 and 4tiansmitted through the duct 'The sliding member is also subjected to the act-ion ot a' spring 29 which tends to move it'upivard and it is connected to the controlling pedal 24 through the medium ot a spring 75.

The position ot the parts shown in Figure l corresponds to release oi' the bralres. lt

the pedal Qt is moved in ain anti-clockwise f direction the slidingY member TS'will move a little downwards .so as to lirst enable the valve 7 to return upon its seating and then to raise the valve S which allows air to enter into the duct 2 and into the releasingcylinder 3. As a consequence the ditlerential pistons Je, 5 are acted upon by the fluid under pressure contained inthe vessel 6 and move downwards as seen in the ligure in such a wav as to displace the 'brake mechanism in the direction tor the application ot the brakes.

As a result ot this admission ot air the partial vacuum decreases in the releasing; cylinder 3 and in the duct fl the. elilect ot 'which is to produce au upward disiiilaceinent ot the sliding; member 75% as a; coi'isequence olz the difference in pressijir'es which the diaphragm 32 undergoes on account oil'the reduction in partial vacuum.

rllhe valve 8, returns to its seat and the brakes are applied with a preesureivhich depends upon the difference between the pressures existing on the one hand in the ve el (i and on the other luind in the rele:` ing ovlinder 3. A fresh displacement ot the pedal 241; in the said direction will allow a new admission ot air to taleplace which will correspond to an increase in the braidingr pressure.

lt is to be noted that the spring 75 becomes compressed to a greater extent in proportion as the pressure increases in the releasing cylinder 3. Upon the return of the pedal in the opposite direction the brakes will be released by operations which are the reverse oit those which take place tor the application of the brakes.

In the case shown in Figure 2 the brake mechanism of each vehicle is connected te all) lllfi piston is constrained to move in the direction corresponding to release. This displacement is obtained by the intervention of a partial vacuum acting upon a piston et connected to the said piston 5. This partial `vacuum is transmitted throughout the Whole length of the train by a duct 57 closed at both ends of the train by plugs 8O and connected to a device producing partial vacuum, formed for example by an ejector 56 supplied by means ot steam, the flow ot which is controlled by a cock 58.

The control of the valves 8 ot the dilerent vehicles is obtained by means of a distributor provided upon each ot the latter and comprising a sliding member 73 adapted to act upon the said valve. This member is connected to a diaphragm 32 upon one. ot the faces ot which acts the partial vacuum existingV in a control `duct 77 extending through theivhole length ci `the train;

The said sliding member is also subjected. through the medium 'of a piston 81. to the action of the pressure existing in the brake cylinder 6 as Well as the .pressure of a spring Q9 acting in opposition to the partial vacuum.

When a partial vacuum exists in the duct 77 the dlaphragms 3Q of the various distributors are raised as Well as the sliding members 73 so that. the valves 8 remain upon their seats, Which prevents any displacement of the pistons 5 in the direction for application of the brakes.

The partial vacuum existing in the duct 77 is controlled by means ot a cock 78 adapted to connect this duct 77 either with the atmosphere through opening 82 or with a source of partial vacuum through a duct 89. T his duct 89 opens into a vessel. 88 in which exists a partial vacuum produced by the ejector 56. This vessel is in fact connected to the duct 57 by a duct or train pipe 90 in which is interposed an automatic valve 72 which opens when the partial vacuum enisting in the said duct 57 is greater than that which exists in the vessel 88.

In order to obtain the control oit the cocks 58 and 78 by the actuation ot' a single lever, these cocks are connected together' by a rod 79. y

It will be seen that the application ot the brakes will be obtained by allowing air to ent-er the control duct 77.

lt is to be noted that ifa cock is provided upon the duct 77 between the vehicle provided With the device producing the partial vacuum and the vehicle coupled to it, it will be possible, by closing this cock belore uncoupling the first of the vehicles mentioned above, to maintain the brakes oit the others in the released position.

With a View to speeding up the braking and in particular the braking ot vehicles which are comparatively distant from the end of the duct 77 through which atmospheric air enters, the distributors of certain. vehicles may be provided with a device producing a direct communication for these vehicles between the duct 77 and the atmospherevvhen the sliding member 73 which they comprise has completed in the direction for the application ot the brakes a stroke exceeding a certain length.

For this purpose provision may be made for the said sliding member 73 to actuate, after it has made a certain displacement, a valve 84 communicating With the atmosphere.

In the case shown in Figure 3 this valve is constantly acted upon by a spring 85 in such a Way as to keep it pressed upon its seat. It is adapted to be positively opened by a bridge piece 83 sccuredto the sliding member 73.

Figure 4 shows that the valve 8 of the distributors may be replaced on the one hand by an automatic valve 8n and on the other hand by a valve 8b secured to the sliding member' 73.

' The spring 29 shown in Figures 2 and 3 is dispensed with and its action is obtained by second diaphragm 32a attached to the sliding member 73 and acted upon one side by the pressure of the vessel 6 and upon the other by the partial vacuum of the control duct 77.

The movements of the said diaphragm 32a are aieeted by the variations in pressure in the vessel 6.

Figure 5 relates to an arrangement which enables the brakes of one setof vehicles to be maintained in released position While the vehicle provided with the device producing the partial vacuum, for example the locomotive, is detached from this set, and this in spite of the small admissions or air which may be produced.

For this purpose vessels 36 are provided upon certain of the vehicles, in which vessels a partial vacuum is produced t'or example by means ot' the partial vacuum which exists when the releases take place in the duct 57: automatic valves 93 being interposed between the vessels 86 and the said duct 57.

The vessels 86 are mounted on an additional duct 87 vWhich entends throughout the Whole length of the train7 the lead being taken form the locomotive. This duct 87 is connected from place to place with the control duct 77 by closing members or cocks 88 `he position of which is shown in Figure 5.

If it is desired' to maintain the brakes in their position of release, it is sudicient to o uf) llt) ai nearest displace one of these closing members 85? in such a Way that it establishes communication between the partial vacuum duct 87 and the control duct 77, this being effected before the said duct 77 is detached from the locomotive, the tivo ducts 77 and 87 being thus cut oill 'from the atmosphere.

From this moment lthe brakes will be maintained in their position of release even after ati'nospheric pressure is re-established in the releasing duet 57. The brakes may be brought back into their applied position it air is made to enter the control duct 57, ior then the sliding members 73 ot' the distributors will separate the valves 8- positively from their seats.

lt is to be noted that the partial vacuum existing in the vessels S6 may be employed Ltor providfng the energy necessary for release when a vehicle is uncoupled.

lt goes Without saying that the control duct 77 may act upon the distributors, Which will consequently be modified, by meansV of compressed air instead of rareiied air.

In this case the vessels S6 shoivn in Figure 5 will also contain compressed air which may be charged by the control duct 77 With he interposition of an automatic valve.

Finally, it is obvious that the various devices described tor producing the control may be employed in combination With any means producing the release oi the brakes, 'for example electroi'nagnetic means.

lVhat l claim is:

l. In a servo brake, provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder7 a controllable communication between said cylinder and a partial vacuum source, and a vessel arranged in said communication and in which a partial vacuum is `maintained.

mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum. source, a 'vessel arranged in said communication and an automatic valve interposed between the said vessel and the partial vacuum source.

3. in a servo li'alre ijii'ovided with brake mechanism, a piston connected to the bralte mechanism and moving in a releasing cyllinder, a controllable connnunication duct between said releasing cylinder and the suction duct oi a combustion engine, and a distrilmtor controlling the entry into action ot the releasing means the part ot said com'- munication duct connecting the releasing comprised between the engine and the distributor having an enlargement.

4l. ln a servo bralre provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder, controllable communicationl duct between said cylinder and a partial vacuum source, a vessel in Which a partial vacuum is maintained, anda distributor controlling the entry into action orf the releasingdevices, said distributor comprising a sliding member `movable in one direction to actuate a closing member controlling communication with the atmosphere, and in the other direction to actua'te a closing member controlling communication withV the duct connected to the partial vaciunn source, said sliding lv t) member seing connected 4to a diaphragm subjected upon one side to atmospheric pressure and upon the other side to the partial if'acuum existing in the releasing cylinder, the displacements or' the said sliding4 men'iber being controlled by the brake. controlling pedal or lever. Y

in a servo brake provided With brake mechanism, apiston connected to the brake ianism and moving in a releasingcylinder, a controllable communication duct betvreen said cr'linder and a partial vacuum source, a resse in. which a partial vacuum is maintained, and a distributor controlling the entry into yaction of the releasing devices, said distributor comprising a. sliding member movable in one direction to actuate sliding member being further subjected to the action of a spring exerting an action Which opposes the action oiatmospheric pressure.

(i. in a servo mechanism, a piston connected to the brake mechanism andvinoving in avreleasingcylinder, a controllable communication duct between said cylinder' and-a partial vacuum source, a vessel in which a partial vacuum is maintained, and a distributor controlling the entry into action ot the'releasing ldevices, said distributor comprising a sliding member movable in one direction to actuate a closing member controllingcommunication With the atmosphere, and in the other direction to actuate a closing member 'controlling communication with the duct connected to the partial vacuum source, said sliding member being connected to a diaphragm subjected upon one side to atmospheric pressure and upon the other side to the partial vacuum existing in the releasing cylinder, the displacements ot' the said sliding member being controlled by the brake brake provided With bralrev lll) Leanser controlling pedal or lever with the interposition ot' a spring.

7. ln a servo brake provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel n which a partial vacuum is maintained, and a diffitributor comprising a sliding member acting by means ot a rocking lever upon closing members which are formed by two valves drawn towards their seats by springs.

8. In a servo brake provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial vacuum is maintained, a distributor controlling the entry into action of the releasing member and a duct in which a partial vacuum is created for operating said distributor.

` 9. In a servo brake provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source,V

a vessel in which a partial vacuum is maintained, a distributor controllingr the entry into action of the releasiingr member and a duct in which a partial vacuum is created for operating said Vdistributor the latter being maintained in the position corresponding to release when a partial vacuum exists in the said control duct which may be put into communication 'with a vessel in which exists a partial vacuum produced by the device which produces the partial vacuum necessary for releasing the brakes.

10. In a servo brake provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial vacuum is maintained, a distributor controlling the entry into action of the releasing member and a duct in which a partial vacuum is created for operating said distributor, the latter being maintained in the position corresponding to release when a partial vacuum exists in the said control duct which may be put into communication with a vessel in which exists a partial vacuum produced by the device whichproduces theV partial vacuum necessary for releasing the brakes, a kinematic connection being provided between the mechanism producing the partial vacuum and a closing member controlling the communication with the said vessel.

ll. In a servo brake provided with brake mechanism, a piston connected to the rodding and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial vacuum is maintained, a distributor controlling the entry into action ol' the releasing member and a duct in which a partial vacuum is created tor operating said distributor, the latter being maintained in the position corresponding to release when a partial vacuum exists in the said` control duct which may be put into communication with a vessel in which exists a partial vacuum produced by the device which produces the partial vacuum necessary for releasing the brakes, a kinematic connection being provided between the mechanism producing the partial vacuum and a closing member controlling the communication `with the said vessel, said closing member enabling the said control duct to be put into communication with the atmosphere.

12. In a servo brake provided with brake mechanism, a pistonconnected to the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial `vacuum is maintained, a distributor controlling` the entry into action ot the releasing member and a duct in which a partial vacuum is created for operating said distributor; the said distributor comprising a sliding member connected A to a diaphragm upon one side of which acts the partial vacuum existing in the said control duet, the sliding member undergoing the action of the pressure existing in the brake cylinder and which is also in opposition to a spring constantly pressing the said member in one direction, which produces the distribution by acting upon a closing member interposed in a duct connecting `the brake cylinder to al vessel containing a iluid under pressure.

13. In a servo brake provided with brake mechanism, a piston connectedto the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial vacuum is maintained, a distributor controlling the entry into action ot the releasing member, a duct in which a partial vacuum is created for operating said distributor; the said distributorcomprising a sliding member connected to a diaphragm upon one side of which acts the partial vacuum existing in the said control duct, the sliding member undergoing the action oi the pressure existing in the brake cylinder and which is also in opposition to a spring constantly pressing the said member in one direction, which produces the distribution by acting upon a closing member interposed in a duct connecting the brake cylinder to a vessel containing a fluid under pressure; means being provided for enabling said distributor to produce comfill lui]

Eli

munication between the control duct and the atmosphere when the said sliding member has completed a stroke exceeding a certain length in the direction corresponding .to release of the brakes.

14.. In a servo brake provided with brake mechanism, a piston connected to the brake mechanism and moving in a releasing cylinder, a controllable communication between said cylinder' and a partial vacuum source, a vessel in which a. partial vacuum is maintained, a distributor controlling the entry into action of the releasingmember and a duet in which a partial vacuum is created for operating said distributor; an additional vessel in which exists a partial vacuum being disposed upon certain vehicles with a View to permitting the brakes to be released without the assistance ot the vehicle provided with the device producing the partial vacuum which is transmitted throughoutthe whole length of the train.

15. In a servo lbrake provided with brake mechanism, a piston connected to the brake mechanism land moving in a releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial vacuum is maintained, a distributor controlling the entry i interaction of the releasing member, a duct in which a partial vacuum is created for operating said distributor; anadditional vessel `in which exists a partial vacuum being disposed upon certain vehicles with a view to permitting the brakes to be released without the .assistance of the vehicle provided with the device producing the partial vacuum which is transmitted throughout the whole length ol the train, said additional vessel being mounted upon an additional duct extending throughout the whole length oit the train, ythe lead being taken from the vehicle provided with the device producing'the par-Y tial vacuum.

16. In a servo brake provided with brake mechanism, a. piston `connected to the brake mechanism and moving in a releasing cylinder, a controllable communication between .said cylinder anda partial vacuum source, avessel in which a partial vacuum is maintained, a distributor controlling the entry ,into action of the releasing member and a duct in which a partial vacuum is created for operating said distributor; an additional vessel in which exists a partial vacuum being disposed upon certain vehicles with a view to permitting the brakes tobe released without the assistance of the vehicle provided with the device producing the partial vacuum which is transmitted throughout the whole length otl the train, said additional vessel being mounted upon an additional duct extending throughout the Whole length oil the train, the lead ,being take-n 'from the vehicle provided with the device producing the partial vacuum7 a closing arrangement allowing the control duct to `be made to communicate either with the, said additional duct or with the atmosphere.

17. In ya Aservo brake provided with l.brake mechanism, a piston connectedto the Vbrake mechanism and moving ina releasing cylinder, a controllable communication between said cylinder and a partial vacuum source, a vessel in which a partial vvacuum `is 1naintained, a distributor controlling the entry into action of the releasing member, a. duct in which a partial vacuumis created for operating said distributor; `an additional vessel in which exists a partial vacuum being disposed upon certain vehicles with a. View topermitting the brakes to be released without the assistance of the vehicle provided with the device `producing' the partial vac uum which is `transmitted throughout .the whole length of the train, a duct provided with an automatic valve ybeing' interposed between the said vessel and the `duct transmitting the partial vacuum which produces the release of the brakes.

18. A servo brake ladapted forruse upon Va train of vehicles in which the braking is obtained `by employing, [for the application of the brakes, `a reserve of energy placed upon each vehicle, releasevbeing obtained by means controlled from one of the vehicles by means of variations kin pressureftransmitted.through a control duct extending .throughout the whole length ofthe train,eaeh vehicle comprising a vessel charged by the said con'-y trol duct and adapted to be employed lfor producing the release otl the brakes of this vehicle when it is separated from the others.

In testimony whereof I alix my signature.

. .HENRI PIEPER. 

